Expansible reamer



April 20, 1948. R. G. FEAR 2,439,968

EXPANS IBLE REAMER Filed sept. 13, 1945 v 24 35 4 .36 as 38 4o 4/ '43 .Z'N VEA/TOR PALPH Gaf-w 0^/ FEA R F017 THB FIR TTO RNE V5' Patented Apr. 20, 1948 UNITED STATES PATENT l OFFICE EXPANSIBLE BEAMER Ralph Gordon Fear, Reseda, Califr Application September 13, 1943, Serial No. 592,147

6 Claims.

My invention relates to a cutting tool, and, since it was rst incorporated in reamers and breaches', such embodiments of myinvention will be Ahereinafter described in detail, and the objects and advantages of my invention incorporated in such Vembodiments will be hereinafter set forth sothat those skilled in the art may readily incorporate my invention in other embodiments of cutting tools. Y

O ne of the objects of rrny invention is the provision of a reamer in which the cutting edges are so formed as to subject the work to a true shearing action as contrasted with the pressural scraping or wiping of the metal from the work asper- `formed by conventional reamers, whereby a perfectly round, smooth and true surface is cut, and gouging, tearing, or biting of the surface of the work is prevented even if the fibers. of the work are not lengthwise of the reamed hole, as Afor example in steel tubing of the welded type.

Vlnother object of my invention is to provide a reamer in which the cutting edges may be formed as a thread by turning in a lathe, thus eliminating the expensive milling operation comedge operative at one time is substantially increased. This substantial increase in the effective length of the cutting edge, together with the formation of the cutting edge so that it exerts a shearing instead of a scraping action, provides Va reamer capable of removing more metal per unit of time land per operation than conventional reamers, while at the same time prolonging the effective life ofthe tool.

Among the other objects of my invention is the provision of a reamer having the cutting edge and Vthe utes so formed that the metal is removed from the Work by shearing action, and the cut metal is removed from the Work, thus avoiding distortion of the cut surface'by the compressive deformation of the metal and by galling due to the passage of the cut metal particles between the lands or cutting edges and the cut surface f the Work.

Still another object of my invention is the proy.vision of :a reamer which maybe readily expanded over a 4Wider range oV diametersthan described, and which has means carried by the t001 `itself for indicating to the Workman the exact degree of expansion of the tool secured for eachgof its adjusted positions, thus enabling the workman,1after determining the diameter of the reamer with a micrometer, to quickly and accurately adjust theV tool to the desired diameter.

.Embodiments of my invention capable of performing the, foregoing objects and providing such advantages are described in the following specincation, which may be better understood by reference to the accompanying drawing. In the drawing, which is forillustrative purposes only,

Fig. lis a side elevational view partially sectioned of a hand reamer embodying my invention;

Fig. 2 is a vertical sectional view taken as indicated by Athe'line 2-2 of Fig. 1;

Y Fig.'3,is aside elevationalview partially sectionedofa rose-reamer of the shell type embodyingrmy invention;

Fig. 1' is a vertical sectional View of an expansible shell reanenlthe sectionV being taken as indicated by the broken line 4--All of Fig. 5;

'Fig'. 5 is an endview of the reamer illustrated in Fig. 4 taken as indicated by the arrow 5;

Fig. 6 is aV vertical sectional view of an expansible. shell reamer during its cutting operation;

Fig. 7 is a sectional vi-ew taken as indicated by FigLS-is an enlarged fragmentary vertical sectional vievvlofM the shell reamerillustrated in Fig.

ve'ntlonal ilutedreamer during its cutting operationll l Referring to the-drawing, which is for illustrative purposes only, the 'numeral Il 'indicates a tool-body provided with two cutting edges I2 and I3' projecting from'and helically disposed relative toithe'tool body Ill in the form of a thread. 'The lcuttingV edges may be inthe formof asingle or multiple thread, the cutting edges I 2 and I3 being illustrated as a double thread of substantially the form of a buttress thread. The provision of the cutting edges in the form of a thread permits them to be cut upon a lathe and obviates the necessity of forming the tool with an expensive milling operation. Adjacent each of the cutting edges I2 and I3 is the usual land I4 intersecting a tooth back I5 Whichis connected Yto a tooth face I6 of an adjacent tooth through ya illet `I'I. Each tooth back I5 with its connected 'tooth face i6 and fillet Il provides a flute I8.

The tool body II and cutting edges I2 and 13' edges I2 and I3 may be spiralled':and'forwardlyv tapered, the amount and. length .of vthistaper. depending upon the size of the rea-mer ,andthe character of Work for which it is intended. vIn a reamer of 3A inch diameter intended for work upon steel such taper may Vbeef thefor'der of 02 inch per inch for 1/2' finchor more. Over -the rearward portion YZ-Illthe cutting edges I2 and I3 are formed of constant diameter. It'will be noted that the lands `I4 and cutting edges-I2 fand'IS are so 'formed that 'they' are dianie'trically'opposed throughout their length, thus permitting the workman to readily determine t'heldiameter at various -lpoints alongv the tool body .I'I -bythe use ofamicro'meter.A y

It will be noted also that the cutting edges-I2 and I3 are so lformed as to'make an acute-angle with the intersected'plane which is'normaltothe axis of the tool body I`I. By formingfthe tool so that this angle is small, lthe -cuttingedge's 'I2 and VI3 andthe vtool .body-III during 'thecuttin'g operation are subjectedto compression stresses substantially circumferentially. of the. tool "body instead vof axially thereof, Tand. the. cutting edges I2 and I`3 yare causedfto exert upon the Work with which they are incontact a true shearing'orpeeling action, .removing a layer of .IfflateriaL'V such as metal, 'from the Work `with the minimum energy and 'leaving the cut 'surface smooth.` Such a shearingor peelingactionis 'radically different from the action 'of a tconventional reamerhavirig its cutting. edges fat -an .angle approximating! 90 degrees, Vwhich action constitutes a :pressural scraping or wiping action removing arlayer 'of material, such as metal, fromthe. work by Compressing it and tearing itlfrom thewo'rk, leaving the cut. surfacerough.. .The Ishearing or;v peeling action resulting from. thedisposition of. thecut.- ting edges I2 and I3 at a verysmallranglewith the intersecting. plane. normal. tov the. axis .o .f .the tool body .Il removes alayert'ofsmateral from the Work Without any..pressuralfdeforrnation. .of the work, even. though theworkbe formed'of a comparatively .resilient metal., .such as. bronze, so that .an absolutely. .holeis formed., Ar/hereas with the .conventional reamer removingthometal by compression of 'the ,worktemporory deformation of the article being cnt causes movementof the. out `silrfaoo arteries passage ortheoutting edge therefrom...resultinain an untrue holle.

The hand reamer illustrated in Fig. 1 includes a shank 2l having at its rearward endajportion 22. .Withits outlingiuthe, formof a'polysoofor reception of a chuck of a conventional actuating device adeptedior rotating .thoreomn 1 `The flutes LI 8 are made of sufficient depth :to

vreceive the material .out fromfthe .work, and.the

formation of the '.flutest iniaright-hand inirecti'on aroundythe tool body .I I .facilitatesithe' feedingof the cut metal forwardlyr'of the holeunthe'work 4 by the right-hand rotation of the reamer so that the cut metal is effectively removed from proximity to the cut surface, eliminating all danger of its passage between the lands I 4 or the cutting edges I2 and I3 and the surface of the Work, and thus preventing the galling or scratching of the cut surface. Further to insure against such galling or scratching of the cut surface the lands I4 aretapered inwardly and rearwardly ofthe tool body I'I' toprfovide the suitable clearance angle, and, to cause the cutting edges to 'cut more I2 and I3 are given a small rake, such for exs .ample jasl to 8 degrees for the first one-third or one-halfr `.ofmthe length of the reamer. The balr'ance is 'cylindrically ground so that it acts as a kburinShing surface to completely remove any irregulaities and leave a smooth surface. Only the forward portion of, the cutting edges I2 and I3 need be initially sharpened, thus prolonging the lifexof the .tool 'by permitting additional portions. .spaced rearwardlyon the tool Ybody to be successyelyiground fas. the :previously sharpened portionsgbecomeworn.

i Illustratedin Fig. 3 is a rosereamerof the shell type, the numeralv 23. indicating a tool. body or shell;V The-tool body23 withan .axial bone 24 includes forward and. rearward portions 25.andx26 flaring rearwardly of the tool body 23 `arida central enlargedportion 2 1.

The toolbodyzfprovided with cutting edges z8 :and 29 isimilarto the. outtingedges |12 and II3 previously described. The cuttng edgefm'ay be in the. form of .'asingle. orimultiplethreed- The Cutting-.edges :28. and. 29 :illustrated in :the drawing are helicallydisposed aroundthe tool body '3, in theformof a double thread, and 4each of :such cutting edgesyis, connected through .e tooth .face.xto. f1i11 et stand tooth. book 32, to a-land 33 of an adjacent outtineedge. .'Here. asin thehand reemer previously described., the connected .tooth .face :3.0. .1i-liet.. 31;, :andtooth back :32. oonsttutoa y.iutofh .the tooth faces 30,;1onds 3.3, andutes 34 heingjiorrned-infthe mennerfand forl the Apur- Doses proviouolvidescribed..

.; r The numerals .ifarid- 36 indicate a -front 4portion. arld...e rear -Dortiom respectively, of lootool rooms. andthe cutting edges. .28.ar1d.1:9 Qrer thefrontrortion th@ .Cutting edges-.23. and 29 are spiralled and tapered forwardly of thewtoo'l- The-cutting eeosend alare angularly'related to, ,theJ intereectinglane normal tothe 'axis of; the. tool rbodyx 23 iin nthe :same manner as the cutting edges I'2' and `I3 fhereinbefore described, andthe operationof thefreamer 'illustrated in Fig 13 fis; similar to Vthe'operation Pof fthe ream'er :illustrated .in fFig.. r`l.

:The formation of =the vreamerrbo dy -2:3 'asi .a shell of courseaifects: a' substantial saving in metal.

11n Fig. .g4 is :illustrated/.an lexpe/risible shell reamenincluding: artoolbodyil'. vflornfed lon the enseres tool body are helical cutting ledges 41 and.48the adjacent cutting edges being connected by a land 49, tooth back 50, fillet 5I, and tooth face 52, the connected tooth face, fillet, and tooth back de- `dining a flute 53, all as previously described.V

The i001 body 4s is provided with an axial here 54 having a rearwardly flared portion 55 at its rearward end and adjacent thereto an enlarged threaded portion 56. Adjacent the enlarged threaded portion 56 the bore 54 is provided with a rearward cylindrical portion 51, and at its forward end the bore 54 is provided with a rearwardly flared portion 58, these two portionsbeing connected by an intermediate cylindrical portion 59. Y Y

Extending through the tool body 46 is a plurality of slots 68, illustrated in Fig. 5 as four in number and symmetrically disposed around the tool body 46. Each of the slots 69 extends from the rearward end of the tool body 46 to adjacent its forward end. As illustrated in the drawing, these slots may extend throughout approximately three-fourths of the length of the tool body 46 and are for the purpose of permitting radial expansion of the rearward portion of the tool body.

Threaded into the enlarged threaded portion 56 of the tool body 46 is an expander plug 6l. This plug 6| is provided .with a rearward tapered portion 62 engaging the flared portion 55 of the bore 54 to expand the tool body 46 as the expander plug 6| is threaded into the tool body.

The expander plug 6l is provided with a rearwardly flared bore 63 cooperating with the fiared portion 58 of the bore '54 to receive a tapered mandrel, such as the mandrel 42, on a suitable arbor for supporting the tool body 46 during its rotation by a suitable actuating machine.

The expander plug 6l is provided with diametically opposed slots 64 in its rearward end for the reception of a suitable tool to effect its rotati-on relative to the tool body 46. The progressive increase in the diameter of the portions 58, 59, and 51 rearwardly of the tool body 46 facili.- tates the expansion of the tool body 46 to a progressively and substantially uniformly greater extent from the forward end of the slots 60 to the rearward end of the tool body 46. Since the slots 60 ydo not extend to the forward end of the tool body 46, it will be seen that the expansionof the rearward portion of the tool body by expander plug 64 therein causes no expansion of the forward portion indicated by the numeral 65 which remains at its-original dimension 'for the continued performance of its function as a cutter and pilot.

The numeral 61 of Fig. 6 indicates generally a reamer of another embodiment of a shell type reamer of my inventi-on. The reamer 61 includes a tool body 68 having formed thereon helical cutting edges 69 and 18. The cutting edges may be formed as a single thread or as multiple threads, those illustrated in the drawing being formed as a double thread. Cutting edges 69 and 19 are connected by a land 1l, a tooth back 12, and a tooth face 13 of the form and dimensions similar to those described in Fig. 1. Each land 1i and connected tooth back 12 and tooth front 13 define a flute 15. The tool body 68 has a forward portion 16 forwardly tapered over which the cutting edges 69 and 10 may be also tapered` and helically arranged.'

The tool body 68 includes also a rearward portion 11 of substantially uniform diameter, the cutting edges 69 and 10 being likewise of substantially uniform diameter. Y

. The tool body sa 1s provided with arl axial tore 18 having an enlargedportion 19 atits forward endproviding an annular shoulder 88. At its rearwardend the bore 18 includes a ared portion 8l for the reception of a tapered portion 82 of a mandrel 83. The mandrel 83 extends to adjacent the forward end of the tool body 68 and is provided with a threaded axial bore 84. Threaded into the bore 84 is an adjusting screw 85 having a head 86 which is received within the enlarged portion 19 of the bore 18 and engages the annular shoulder 89 of the tool body 68. i

VThe mandrel 83 is a part of an arbor 81 which is provided rearwardly of the tapered portion 82 with a. threaded portion 88. A collar 89 is secured upon the threaded portion 88 and provides a forwardly flared bore 99V adapted for engaging a rearwardly taperedportion 9| of the tool body 68` at its forward end. Rearwardly of the threaded portion 88 the arbor 81 provides a shank 92 for reception in a chuck of a suitable actuating machine for rotating the reamer 61.

Formed on the shank 92 adjacent the threaded portion 88 is a scale .93 and indicia or numbers 94, and formed on the rearward end of the collar 89 is indicia for cooperating with the scale 93 and indicia 94. The indicia upon the collar 89 may be an arrow, groove, scratch, or projection 95 radially disposed to indicate upon the scale 93 and with the numbers 94 the degree or extent of relative rotation of the collar 89 and the arbor 81. A plurality of slots 96 similar to the slots previously described are formed in the tool body 68 terminating short of its forward end.

With the tool assembled asillustrated and described, if it is desired to expand the rearward portion 11 of the tool body 68 Yand the cutting edges 69 and 18, the collar 89 is rotated rearwardly onI the threaded portion 88 to the desired extent, and thereafter the locking screw is rotated to move the tool body 68 rearwardly on the arbor 81. This rearward m-ovement is continued until the tool body 68 is securely locked upon the mandrel 83 betweenthe head 86 of the locking screw 85 and the fiared bore 99 of the collar 39. During such movement of the tool body 68,' the engagement of the forwardly Vtapered portion 82 ofthe mandrel 83 with the flared bore 8| of the tool body 68 causes the expansion of the tool body 68 of its rearward portion 11. The pitch of the threads of the threaded portion 88 of the mandrel 83 and the cooperating threads of the collar 89 and the degree of taper of the tapered portion 82 of the mandrel and the cooperating flared bore 8i of the tool body 68 are so related that relative rotation of the collar 89 and arbor 81 to a predetermined extent accomplishes the expansion of the rearward ends of the cutting edges 69 and 10 to an exact predetermined degree.

The degree of expansion per given unit of rotation of the collar 89 upon the arbor 81 measured diametrically, radially, or circumferentially in any desired units is represented by the scale 93 and the numbers 94. A workman, having measpushing or shoving upon thelayertoaccomplish l its separation from the work by a :tearing .or scraping action. .Suchanaction inevitably leaves the cut surface |02 of.theworkpittedyroughened, andV scufted. Furthermore, in suona .process of metal removal .dependent entirely upon. thefsubjection of the YWork to compressive .stness,.there is a tendency for the work vadjacent the point .of Contact with the cutting .edges 99 tobecomede- :formed or increased in density. responsiveftosuch compression, which tendency. is sovmarked in: the case of materials havingfthe `resilientproperties of bronze thatthe.compressedsportions of A`the work expand inwardly when the compression .thereon isrelievedby thepassage ofthe cutting edge .99, thus providinga -hole which is Vnot'trlue or ofY uniform dimensions..

All of the4 embodiments vofmy invention hereinbefore illustrated and described. operate :with that shearing or peeling action :subjectingthe work to theminimum .of compressive .stressesas describedy in connection with. theembodiment illustrated in Fig. 1.

Preferably` inthe embodiments ef my. invention lemployed as reamers or broaches therearward l.portion of the cutting edges overawhichthe cuttingedges `are of substantiallyuniform diam? -eter are made of sufficient length that'the .walls of the Work are cutnot. only to theexact-desired form, but they are also givenamirror nish so vthatthe roaming-or breaching andfmishingzare accomplished ina singleoperation. If. desired, 'the cutting edges at therearwardend of the tool Amay be maintained dull or -unsharpened and made of a slightly greater diameter thanthe'cub lting edges forwardly thereof so thatinfoneop- .eration of the tool the Walls are cut. to exactly- -the desired form and then burnished.

From the foregoing it willbe understoodthat my invention may be embodied in hand reamers, fiuting chucking-reamers, rose chucking reamers, shell reamers, taperreamers, and various other types of reamers, push or pu-llfbroacheaxmilling :cuttersfand Various other cutting tools.

Whilev those embodimentsofmy invention herefinbefore described perform theobjects-'andprovide the advantages primarily stated, various mo'dications of such embodiments and other embodiments including my mental concept-will occur to those skilled in the rart from theforegoingr description, and'I therefore wish my invention not to be restricted to thespecic forms illustrated and described, butincludingallthose modifications and other embodiments ,coming within the scope of the claims whichfollow.

I claim. as my invention:

l. In a cutting tool, the combination oiza tool body having arbore. extending therethrough, said bore being Vflared at the rearward .endo said tool bodypand saidbody having a slot'in its rearward portion; a helical cutting .edge projecting from said tool body, said cutting edge being formed at such an acute angle with the plane normal-to the axis of saidtoolbody-as to out acontacting 4surface Vwith a shearing action; la mandrel disposed in said bore, said mandrel having a tapered portion extending into said flared bore; and-means for securing said 'body in variousfpositions-upon said mandrel, whereby the diameter of saidcutting edge on SaidrearWard-'portion-ofrsaid body is'v'aried.

8 .2...In...a cutting tool, the. combination oi: a toolbody havinga bore extending therethrough, said-.bore being. dared fat therearward end of said tool body and-said body. having. aslotin .itsrear- Wardmortion; a f helical cutting wedge. projecting .from...said tool body, Asaid .cutting edge being formed. atsuchan .acute angle with the plane normallto .the `axis ofsaidtool .body `as. to cut a contactingfsurface with ashearing action; amandrel disposediin-saidv bore, `said mandrel having a tapered portion extendingiinto` .said flaredbore; meansrforssecuring said. body invarious. positions upon saidmandrelywhereby. the V:diameter of said cutting, edge on. saidrearward portion of said body is varied; and indicia means associated with said mandrel and indicating by Lthe .position of said-body on said mandrelI the degreeof expansion yorsaid body .at all ofits operative positions onsaid mandrel.

.3.1Ina cutting. tool, the `combination of a. tool body. having azbore there-inA and a :slot in its. rearwardportion, said bore being dared at-the rearward. endof saidbody;V a cuttingfedge lextending aroundsaidv tool body` .and Vangularlyn related to the plane. normalv totheaxis offsaid body,where by said edge cuts a contacting surfaceby shear; a mandrelrpositionedwithin .said bore, saidrmandrelhavinga tapered portion extending. into said flaredrbore-a lockingmember threaded into said mandrel against `said tool body, whereby said body is advanced-on.said taperedlporticn of said mandrel; Vanda Ycoll-arlthreaded upon .said mandrelragainstsaid .tool body. and :with said locking member clamping said body against movement on :said..mandre1.

:4.11m a1 cuttingtool,v the. combination of: a tool body having-a: bore. therein and .a slot in itsrearward portion,said bore beinglflared. atlthe rear- .ward'end `cfwsaid body; a cutting edge extending around said tool; body rand. angularly vrelated to the `plane lnormalto-the axis ofsaid body, wherebysaid-edge vcuts a contactingwsurface by shear; amandrel positioned vWithin said bore, said mandrel havinga-,tapered portion extending-into said flared#Y bore; a :locking-member threaded into said mandred-:vagainst said tool "body, whereby said bodyis advanced onsaid taperedportionof said mandrel; -.a collar 2 threaded upon said mandrel against-.said tool-bodyy and withsaid lockingmember. clamping saidA body against movement on said mandrel; and indicia'- means uponsaid collar and saidsmandrel adjacent said collar, the pitch of the threadedvconnection-of saidcollar and said mandrel beingsorelatedf to the degree of-'are of said flared bore and the degree of taper of'said taperedportion of'said mandrel that said'indicia means indicates the-degree ofexpansioin of lsaid lo'dyat all. of :its operative positions onsaid man- -5. In .acuttingtoolthe combination cfr a tool bodyfihaving a bore: thereinand a slot in its rearward'portionr-said :bore-being flared at the-rear wardendofsaid body and said' body having a rear- Wardly tapered portion at .itsrearward `end; a

' cutting. edgeextending.. around said tool body and angularly relatedLtothe'plane normal to the axis of;.saidbody,.whereby;.said edge cuts-a contacting surface b.y-shear; aI-mandrel `positioned within said-bore, said-mandrel having a'tapered-portion extendinginto said. flared bore; allockingmember threaded into said mandrel ...against said tool body, whereby saidbody .is advanced :onfsaid tapered portion; of' -said mandrel; .a collar threaded upon saidozmandrel, .saidcollar having `a flared portion engaging saidtapered portion of's'aidtool body and with said locking member clamping said body against movement on said mandrel; and indicia means upon said collar and said mandrel adjacent said collar, the pitch of the threaded connection of said collar and said mandrel being so related to the degree of nare of said flared bore and the degree f taper of said tapered portion of said mandrel that said indicia means indicates the degree of expansion of said body at all of its operative positions on said mandrel.

6. In a cutting tool, the combination of: a tool body having a bore therein and a slot in its rearward portion, said bore being flared at the rearward end of said body and being provided with a recessed shoulder at the forward end of said body, and said body having a rearwardly tapered portion at its rearward end; a cutting edge extending around said tool body and angularly related to the plane normal to the axis of said body, whereby said edge cuts a contacting surface by shear; a mandrel positioned within said bore, said mandrel having a, tapered portion extending into said flared bore; a locking screw threaded into the forward end of said mandrel against said recessed shoulder, whereby said body is advanced on said tapered portion of said mandrel, the head of said locking screw being substantially flush with the forward end of said tool body; a collar threaded upon said mandrel, said collar having a ared portion engaging said tapered portion of said tool body and with said locking member clamping said body against movement on said mandrel; and indicia means upon said collar and said mandrel adjacent said collar, the pitch of 10 the threaded connection of said collar and said mandrel being so related to the degree of flare of said flared bore and said tapered portion of said mandrel that said indicia means indicates the degree of expansion of said body at all of its operative positions on said mandrel. i

RALPH GORDON FEAR.

REFERENCES CITED The following references are oi record in the file of this patent:

UNITED STATES PATIENTS Number Name Date 1,210,391 Alexander Jan. 2, 1917 1,266,538 Alexander May 14, 1918 1,321,243 Pettersen et a1. Nov. 11, 1919 1,347,740 Hack July 27, 1920 1,479,079 Kutchera Jan. 1, 1924 1,531,891 Wetmore Mar. 31, 1925 1,654,610 Seiler Jan. 3, 1928 1,697,509 Marty, Jr. Jan. l, 1929 1,902,062 Evans Mar. 21, 1933 2,084,737 Magnus June 22, 1937 2,376,021 Vosper May 15, 1945 FOREIGN PATENTS Number Country Date 24,300 Great Britain 1902 546,245 Germany Mar. 12, 1932 OTHER REFERENCES Railway Mechanical Engineer, Mar. 1943, p. 129, Spiral Reamer. 

